Dear Matteo,
I found a one-liner solution to this problem:
n <- 100
data.table(i0 = 100)[, (paste0("i", 1:n)) := 100]the data.table(i0=100) creates a one column-one row data.table, Between the [] brakets i create a column name vector with paste, and surround it with () to make it recognised as names (for details, look at the Dateails of ?`:=`), and it will append columns to the i0 data.table. This cannot be done with a 0-column data.table. Good luck: András Tajti On 16 December 2015 at 12:53, Matteo Richiardi <matteo.richia...@gmail.com> wrote: > I apologise for this very basic question, but I found no answers on the > web. > I want to create a data.table with n columns, named i1 ... i'n', with only > one row with value = 100 for every variable. > > I can do it "by hand": > > M.dt <- data.table(i1=100,i2=100,i3=100) > > but I would like to make it in a loop, as 'n' is large in my case. > > > Thanks. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
